STYLE: Prefer in-class {} member initializers

Prefer using in-class `{}` member initializers in
`itk::ParallelSparseFieldLevelSetImageFilter` for its non-static data
members.

Related to commit 5e2c49f.

Author: jhlegarreta

Modules/Segmentation/LevelSets/include/itkParallelSparseFieldLevelSetImageFilter.h

@@ -125,14 +125,14 @@ class ITK_TEMPLATE_EXPORT ParallelSparseFieldCityBlockNeighborList
 
 private:
   char                      m_Pad1[128]{};
-  unsigned int              m_Size;
-  RadiusType                m_Radius;
-  std::vector<unsigned int> m_ArrayIndex;
-  std::vector<OffsetType>   m_NeighborhoodOffset;
+  unsigned int              m_Size{ 2 * Dimension };
+  RadiusType                m_Radius{};
+  std::vector<unsigned int> m_ArrayIndex{};
+  std::vector<OffsetType>   m_NeighborhoodOffset{};
 
   /** An internal table for keeping track of stride lengths in a neighborhood,
    *  i.e. the memory offsets between pixels along each dimensional axis. */
-  unsigned int m_StrideTable[Dimension];
+  unsigned int m_StrideTable[Dimension]{};
   char         m_Pad2[128]{};
 };
 

Modules/Segmentation/LevelSets/include/itkParallelSparseFieldLevelSetImageFilter.hxx

@@ -49,7 +49,6 @@ ParallelSparseFieldCityBlockNeighborList<TNeighborhoodType>::ParallelSparseField
   NeighborhoodType it(m_Radius, dummy_image, dummy_image->GetRequestedRegion());
   nCenter = it.Size() / 2;
 
-  m_Size = 2 * Dimension;
   m_ArrayIndex.reserve(m_Size);
   m_NeighborhoodOffset.reserve(m_Size);